Machines for continuously forming sand piles

ABSTRACT

A machine for continuously forming sand piles comprises a casing with a hopper connected thereto near its upper end. A vibratory pile driver is mounted at the upper end of the casing above the hopper and a ram is mounted in the casing for undergoing reciprocatory movement therein under the action of a drive means which is independent of the pile driver. The ram carries a tamping plate at its lower end and in the lowermost end stroke position, the tamping plate is located a small distance above the lower end of the casing. As the casing is being lifted from the ground after being sunk therein and sand has been supplied to the casing via the hopper, the ram is reciprocably moved in the casing as the latter is continuously lifted and while the vibratory pile driver is continuously operated.

United States Patent 51 3,648,467

Ogawa Mar. 14, 1972 [54] MACHINES FOR CONTINUOUSLY FOREIGN PATENTS ORAPPLICATIONS FORMING SAND PILES Mitsuro Ogawa, 31, l chome,Tanabehonmachi, Higashisumiyoshi-ku,, Japan Filed: Apr. 23, 1970 Appl.No.: 31,324

Inventor;

[30] Foreign Application Priority Data Aug. 27, i969 Japan ..44/68l70U.S.Cl ..6l/53.64,6l/ll,6l/63 Int. Cl. .E02d 5/38, E02d 7/38, E02d 3/10Field oiSearch ..6l/ll, 13,535, 53.64, 53.66,

[56] References Cited UNITED STATES PATENTS 3,498,066 3/1970 Nishimuraet a] ..61/1 1 3,420,063 III 969 Bodine, Jr ..61/11 3,184,924 5/1965Stanau ..6l/53.64 X

296,908 I917 Germany ..6l/53.52

Primary Examiner-Jacob Shapiro Attamey-Waters, Roditi, Schwartz & Nissen[57] ABSTRACT A machine for continuously forming sand piles comprises acasing with a hopper connected thereto near its upper end. A vibratorypile driver is mounted at the upper end of the casing above the hopperand a ram is mounted in the casing for undergoing reciprocatory movementtherein under the action of a drive means which is independent of thepile driver. The ram carries a tamping plate at its lower end and in thelowermost end stroke position, the tamping plate is located a smalldistance above the lower end of the casing. As the casing is beinglifted from the ground after being sunk therein and sand has beensupplied to the casing via the hopper, the ram is reciprocably moved inthe casing as the latter is continuously lifted and while the vibratorypile driver is continuously operated.

7 Claims, 17 Drawing Figures PAIENTEBMAR 14 I972 SHEET 1 BF 3 FIG. 2

I II 1 I'M FATENTEU MAR 14 1972 DEPTH SHEET 2 [1F 3 PATENTEUMAR 14 I9723,648 A67 SHEET 3 [If 3 HG 9 HG l0 TIME E 2 s Q (3 PRIQR ART l! FG.PRIOR ART TIME CIEPTH MACHINES FOR CONTINUOUSLY FORMING SAND PILES Thepresent invention relates to machines for continuously forming sandpiles which are to be settled in the soft ground for the purpose ofstabilizing the soft ground.

As a method of stabilizing the soft ground, there has been known aso-called Sand Drain Method whereby a large number of sand piles aresettled in the soft ground and then a load is imposed on the groundsurface thereby causing the water contained in the soft ground to bedischarged to the ground surface by way of drain formed by theabove-mentioned sand piles thus dehydrating and hardening the soil.

Furthermore, there has been known another method whereby a large numberof compacted sand piles, each having a diameter larger than that of thecasing pipe adapted to settle said sand piles, are formed in the softground and a pressure is applied by each pile to the surrounding softground, respectively, thereby causing water within the soft ground to bedischarged rapidly to the ground surface through said sand piles, thuscompacting, dehydrating and hardening the soft ground ranging from thedesired depth to the ground surface.

The sand pile forming machines used in the above-mentioned two methodsfor forming sand piles-are mostly of the type provided with a vibratorypile driver at the top of the casing pipe on account of a good executingefiiciency.

However, in the conventional methods of forming sand piles utilizing thepile forming machines of the above type, there exist the followingdefects, i.e., in the sand drain method as mentioned above utilizing theconventional type sand forming machine, the process of sand pile formingis carried out in the following manner; that is, at first the vibratorypile driver of the machine is actuated to drive the casing pipe into thesoil down to a predetermined depth. The casing pipe is then filled withsand inside thereof, and thereafter, while the vibratory pile driver isstill being operated, the casing pipe is pulled continuously upward,thus forming a sand pile.

In the above method of sand pile forming, the sand pile formed in theground in many cases is not effective enough to serve as a drain eitherby having its diameter rendered too small at some point or by being cutoff due to the pressure of the surrounding soil. If the sand within thecasing pipe is compacted for the purpose of eliminating the abovedefects, the sand would be plugged inside the casing pipe. Thus, itbecomes difficult to discharge the sand downwardly from the casing pipeduring the pull-out process of said casing pipe, and as a result thesand pile to be formed would rather be cut off in the process.

Next, a sand pile being compacted and having a diameter larger than thatof the casing pipe is formed in the following manner with theabove-mentioned conventional machines for forming sand piles. That is,after the casing pipe has been driven to a predetermined depth into thesoil by actuating the vibratory pile drive, the casing pipe is pulledslightly upward while the vibratory pile driver is being operated. Thecavity created at the lower portion of the casing pipe by the abovepulling action is then filled with sand. This sand is fed into thecasing pipe from the top thereof. The casing pipe is again driven-in soas to cause the sand fed down into the above cavity to be compacted.Then, the casing pipe is again pulled slightly upward, thereafterrepeating the same process until a compacted sand pile is formedconsecutively up to the ground surface.

Therefore, the repetition of pulling-out and driving-in of the casingpipe is the essential operation required for the forming of a compactedsand pile having a diameter larger than that of the casing pipe whenusing the conventional sand pile forming machines. In the process offorming such a compacted sand pile, the compacted sand pile being formedwill have such a shape that resembles inverted cones piled up, ratherthan having a unifonn diameter throughout its length, in the case whenthe ground is extremely soft. Consequently, it is impossible to obtain acompact sand pile with a uniform diameter throughout its length unlessthe cycle of pulling and driving the casing pipe is made very small. Forthis reason, it is impossible to increase the executing efficiency offorming a compact sand pile with the conventional sand pile formingmachines.

Next, the process of discharging the sand toward the lower portion ofthe casing pipe, when pulling out the casing pipe, will be describedhereinafter.

Even if the sand being supplied into the casing pipe is caused tovibrate and is turned into a fluidal state by the vibration of the pipedue to the operation of the vibratory pile driver, the discharging ofthe sand toward the lower portion of the casing pipe will be preventedby additional mechanisms provided at the lower portion of the casingpipe, such as a narrow portion or an opening and closing cover, thusmaking it difficult to discharge the sand smoothly. Therefore, for thepurpose of improving the sand discharging process, there has beenadopted conventionally a method whereby sand is discharged forcibly bysending compressed air into the casing pipe. In the case when thedischarged quantity of sand is small with respect to the withdrawingvolume of the casing pipe, even though the method of sending compressedair is adopted, the sand pile to be formed becomes slender by thepressure of the surrounding soil or by the pressure of excess pore waterand also is disrupted halfway due to the surrounding soft soil beingbackflowed into the casing pipe. Therefore, the continuity of the sandpile to be formed] in many cases becomes difficult to obtain even if thesupply of sand is sufficient with respect to the total sand quantity ofthe sand pile.

It is an object of the present invention toeliminate the above-mentioneddeficiencies inherent in the sand pile forming process using theconventional sand pile forming machines by providing an improved sandpile forming machine capable of continuously and efficiently fonning,not only a sand pile having almost the same diameter as that of thecasing pipe used in the sand drain method, but also a compacted sandpile having a diameter larger than that of the casing pipe.

It is another object of the present invention to provide an improvedsand pile forming machine capable of continuously forming a sand pilewhich has a desirable shape with a uniform diameter throughout itslength, there being no disruption nor any irregularly narrow portions.

It is still further object of the present invention to provide animproved sand pile fonning machine capable of freely and continuouslyforming a compacted sand pile whose diameter varies along it length soas to be well-adapted to the characteristics of each of the differentlayers of the soft ground.

The characteristic features of the sand pile forming machine accordingto the present invention, for the purpose of attaining the the aboveobjects, consist in that a forcibly and vertically reciprocatingmechanism, which. is to be driven by a driving means other than theabove-mentioned vibratory pile driver, is provided inside the casingpipe and at the upper portion of the sand feeding hopper of the casingpipe with the vibratory pile driver disposed at the top portion thereof,whereby the upper end of a ra'mmer being inserted into said casing pipeis connected to the forcibly and vertically reciprocating mechanism. Therammer is provided at its lower end with a tamping plate. The rammer andthe tamping plate are then caused to perform by force a verticallyreciprocating motion, respectively, within the casing pipe, as theresult of the operation of said forcibly and vertically reciprocatingmechanism. Moreover, the tamping plate is disposed such that at itslowest movable point, the position of said tamping plate is to besituated at a small distance above the lower end of the casing pipe.

The characteristic features of the present invention will become moreapparent from the following descriptions with reference to the appendeddrawings.

FIG. 1 is a side view, partly in cross section, showing an embodiment ofthe machine for continuously forming sand piles according to the presentinvention, which illustrates in block diagram the driving source of aforcibly and vertically reciprocating mechanism utilizing a hydraulicpiston;

FIG. 2 is a sectional view taken along the line A-A of FIG.

FIG. 3 is a perspective view of an embodiment of the compacting platecomposed of a plurality of radial vertical plates in the machineaccording to the present invention, with the lower portion of the casingpipe partly cut out;

FIG. 4 is a side view of an embodiment of the compacting plate composedof an opening and closing plate made of a pair of semicircular platesbeing connected with each other by a hinge in the machine according tothe present invention, with the lower portion of the casing pipe partlycut out;

FIG. 5 illustrates the relation of the vibrations and periodic pressureapplications imposed on the sand at the lower portion within the casingpipe beneath the compacting plate in the case of forming a sand pileusing the machine according to the present invention;

FIG. 6 illustrates the stages of the sand pile forming process carriedout by the machine according to the present invention;

FIGS. 7 through illustrate the relationships between the diameter of thesand pile to be formed by the machine according to the present inventionand the pulling speed of the casing pipe; in which FIG. 7 is a graphicrepresentation showing three different pulling speeds at which a casingpipe driven to a predetermined depth is pulled out continuously andalmost at a uniform speed;

FIG. 8 illustrates the shapes of three sand piles formed, eachcorresponding to the pulling speeds shown in FIG. 7, respectively;

FIG. 9 is a graphic representation showing the stage in the process inwhich a casing pipe being driven into the soil to a predetermined depthis pulled out, the pulling speeds being made to vary;

FIG. 10 illustrates the shape of the sand pile formed at the pullingspeeds shown in FIG. 9;

FIG. 1 l is a graphic representation showing, as a reference, therelationship between the pulling and driving of a casing pipe in case offorming a compacted sand pile with a diameter larger than that of thecasing pipe using a conventional sand pile forming machines; and

FIG. 12 illustrates, as a reference, the shape of a sand pile formed bythe repetition of pulling and driving of a casing pipe as shown in FIG.11.

FIGS. 1 and 2 shows respectively an embodiment of the machine forcontinuously forming sand piles according to the present invention, inwhich a vibratory pile driver 2 is attached at the top of the casingpipe 1 for use in forming sand piles. An oil pressure piston 3, which isa forcibly and vertically reciprocating mechanism, is at attached at theupper portion within said casing pipe 1. This oil pressure piston 3 isdriven by a driving source other than said vibratory pile driver 2, thatis, the piston 3 is driven by an outside driving source comprising anoil pressure unit 4, electromagnetic servo-valve 5 and a control device6 therefor. Next, a rammer 7 is inserted into the above-mentioned casingpipe 1; the upper end of the rammer 7 is connected to the oil pressurepiston 3; and the lower end of the rammer 7 is attached to a circulartamping plate 8, said rammer 7 and tamping plate 8 being so constitutedas to perform a forcibly and vertically reciprocating motion by theoperation of the oil pressure piston 3. The tamping plate 8,furthermore, is so disposed that at its lowest movable point, thetamping plate is situated at a small distance above the lower end of thecasing pipe. Moreover, swing stopping plates 9 of a radial shape aresecurely attached to the rammer 7, said plates 9 being disposed at anappropriate distance from each other. The plates 9 serve to preventtransverse swing in case of the vertical movement of the rammer 7, inaddition to aiding the downward flow of sand supplied from the hopper10. In the machine of the present invention as described above, thevibratory. pile driver attached to the top of the casing pipe 1 can beof thetype wherein the casing of the vibration generatconnected directlyto the casing pipe 1, or of the type wherein an impact convertingmechanism is provided between the casing of the vibration generatingmechanism and the casing pipe 1.

In the embodiment as shown in FIG. 1, there is illustrated the oilpressure piston 3 is the forcibly and vertically reciprocatingmechanism. This mechanism is by no means limited to an oil pressurepiston, and it is possible to adopt other forcibly and verticallyreciprocating mechanisms of appropriate types.

Furthermore, the tamping plate provided at the lower end of the rammer 7should not be limited to the one as shown in FIG. 1, and it is possibleto use, for example, the type as shown in FIG. 3 wherein vertical plates8' are securely attached in radial form to the lower end of the rammer7. The rammer may also be as shown in FIG. 4 wherein an opening andclosing plate consisting of a pair of semicircular plates 8" are joinedtogether by a hinge and can be opened only in downward direction in aninverted V shape.

The embodiments of the machine for continuously forming sand pilesaccording to the present invention as explained heretofore, and now thesand pile forming for the purpose of stabilizing the soft ground byusing the machine of the present invention shall be described in detailhereinafter.

First, with reference to FIG. 6 the process of forming a compacted sandpile having a diameter larger than that of the easing pipe in the softground and the operation of the machine shall be explained.

As shown in FIG. 6 (a), a sand plug 11 is provided at the lower end ofthe casing pipe 1 of the machine according to the present invention. Asshown in FIG. 6 (b), the vibratory pile driver 2 is actuated and thecasing pipe 1 is driven into the soft ground to the required depth.Then, an appropriate quantity of sand is supplied from the hopper 10into the casing pipe 1. The supply of the above-mentioned sand iscarried out during the process of pulling out the casing pipe 1 to bedescribed hereinafter. Next, as shown in FIG. 6 (c) and (d), while thevibratory pile driver 2 is being operated continuously, the easing pipe1 is pulled out continuously upward at an appropriate speed simultaneouswith the actuation of the forcibly and vertically reciprocatingmechanism 3 during the above pullingout process. While the sand 12flowing downward beneath the tamping plate 8 is being compacted at thelower end inside of the casing pipe I, the sand 12 is forciblydischarged from the lower end of the casing pipe by means of the tampingplate 8 thereby forming continuously a compacted sand pile l3 having adiameter larger than that of the casing pipe 1.

In the process of forming a sand pile 13 as shown in FIG. 6, the pullingspeed of the casing pipe 1 is comparatively slow so that the sand pile13 thus formed will be a compacted sand pile with a diameter larger thanthe diameter D of the casing pipe 1. However, if the pulling speed isincreased, the sand pile formed will have a diameter substantially equalto the diameter D of the casing pipe 1. The relationship between thepulling speed of the casing pipe I and the diameter of the sand pileformed is asshown in FIGS. 7 and 8. Through the relationship between thepulling speed of the casing pipe I and the diameter of the sand pile tobe formed prior to the actual work it becomes possible to freely formnot only a sand pile 13' with a diameter substantially equal to thediameter D of the casing pipe I as shown in FIG. 8 (a) but also acompacted sand pile 13 with a diameter larger than that of the casingpipe I as shown in FIG. 8 (b) and (c), by means of the machine accordingto the present invention.

Furthermore, as shown in FIGS. 9 and 10, it is also possible to freelyform a sand pile 13' whose diameter varies along its length by causingthe pulling speed of the casing pipe to be changed during the pullingprocess. It is therefore possible to form a compacted sand pile whosediameter changes in accordance with each layer of the ground in caseswhen the characteristic of the soft ground changes in a layer pattern.

Next, the compacting and forcible discharging of sand in the sand pileforming process using the machine of the present invention shall beexplained hereinafter. When the casing pipe 1 is subjected to thepulling process after the casing pipe 1 has been driven into the soildown to a predetermined depth, the vibration created by the vibratorypile driver and imparted to the casing pipe 1 is also imparted to thesand being supplied previously into the pipe 1. The sand is then causedto flow downward within the pipe 1 beneath the tamping plate 8 in afluidal state. As shown in FIG. 5, this sand is subjected to a vibratoryperiodic pressure (V,,+V,), i.e., the sum of the vibration V, of thecasing pipe 1 with the forcible, vertical, reciprocating motion V of thetamping plate 8. It has been recognized in soil mechanics that a staticpressurizing is effective in addition to vibration in sand compacting byvibration, so that the sand flowed down beneath the tamping plate 8 bythe above-mentioned vibration and the periodic pressure (V,,+ V iscompacted effectively at the lower end and inside of the casing pipe 1.Furtherhomre, the sand is forcibly discharged from the lower end of thecasing pipe 1 by the stroke of the tamping plate 8. In the case when theadded pressure from the tamping plate 8 exceeds the bearing capacity ofthe sand pile to be formed thereunder, the said to be discharged will beenlarged outwardly outside of the outer periphery of the casing pipe 1as the pulling action of the casing pipe 1 has halted.

Consefiiueiitly, as described heretofore, it becomes possible to freelyand continuously form a compacted sand pile with a diameter larger thanthat of the casing pipe 1, without forming a sand pile having the samediameter as that of the casing pipe 1. In the case when the bearingcapacity of the sand pile to be formed is larger than the pressureapplied by the tamping plate 8, it is also possible to automaticallyraise the entire machine, including the casing pipe, by the reaction ofthe pressure applied to the tamping plate 8 while forming the sand pile,without lifting the entire machine by a rope or the like during theprocess of pulling-out the casing pipe 1.

Next, the vibration of the vibratory pile driver 2 and the forcibly andvertically reciprocating motion of the forcibly and verticallyreciprocating mechanism 3 will be explained hereinafter. The vibrationV, to be imparted to the casing pipe I by the vibratory pile driver 2 isnormally about 400 to 1,500 c.p.m. in frequency and to 30 mm. inamplitude. Whereas, the forcible, vertical, reciprocating motion (V tobe imparted to the tamping plate 8 by the forcibly and verticallyreciprocating mechanism 3 is about 30 to 60 c.p.m. in frequency andabout one-sixth D to D in stroke (D is the diameter of the casing pipe 1to be used). The values of V, and V given above are considered practicalfrom the viewpoint of the output of the forcibly and verticallyreciprocating mechanism 3. Moreover, it has been determined throughexperiments that those values are appropriate from the standpoint ofmaintaining uniformity in the diameter of the sand pile to be formed.

The above-mentioned frequency should be adjusted properly within therange of 30 to 60 c.p.m. depending on the water content of the sand tobe used, the size of the sand grain, and the quality of the sand or thelike. Moreover, such an ad justment can be effected by means of thecontrol device 6 of the electromagnetic servo-valve 5 in the case of theembodiment shown in FIG. 1.

Next, the shape of the tamping plate 8 will be described. It isnecessary to pay special attention to the shape of the tamping plate 8in order to effectively compact the sane supplied into the casing pipe 1and, furthermore, to cause the sand to flow smoothly downward beneaththe tamping plate 8. In the case of the embodiment as shown in FIG. 1,the upper portion of the tamping plate 8 is formed with a conical shapeso that the sand will encounter only a small resistance therefrom as thetamping plate 8 moves upwardly, and, moreover, the sand can flowsmoothly downwardly beneath the tamping plate 8 through a gap betweenthe tamping plate 8 and the inner wall of the casing pipe 1. In the caseof the embodiment as shown in FIG. 3, the tamping plate 8 is composed ofthe plurality of vertical plates 8' securely attached to the lower endof the rammer 7 in a radial pattern, so that when the tamping plate 8 ismoved upward the resistance encountered by the sand is very small and,furthermore, the sand can flow easily downwardly between the radiallyformed vertical plates 8'. In the embodiment as shown in FIG. 4,. on theother hand, the tamping plate 8 is an opening and closing plate which isopened only downwardly in an inverted V shape, and is formed by the pairof semicircular plates 8" joined together by a hinge, so that the sandwill encounter a small resistance when the tamping plate 8 movesupwardly, and furthermore the sand can flow smoothly downwardly in thegap between the inner wall of the casing pipe 1 and the tamping plate 8.

In the embodiments of the tamping plate 8 as shown in FIGS. l and 3described heretofore, the area of the transverse section of the tampingplate 8 is about one-fourth of the area of the hollow section of thecasing pipe 1. The above-mentioned area ratio between the hollow sectionof the casing pipe 1 and the cross section of the tamping plate 8 hasproven to be best as the result of experiments.

Next, the position of the tamping plate 8 within the casing pipe 1 willbe explained. In the process of forming a sand pile by the machineaccording to the present invention, the sand being supplied into thecasing pipe 1 is compacted at the lower end within the casing pipe 1beneath the tamping plate 8 in a state restricted to the wall of thesaid casing pipe 1. The sand thus compacted is extruded from the lowerend of the casing pipe II by means of the tamping plate 8. Therefore, itis necessary to arrange the tamping plate 8 such that when the tampingplate 8 has been moved to its lowest point the lower end thereof will besituated at an appropriate distance above the lower end of the casingpipe 1. However, if the above-mew tioned distance is too great, the sandwill be plugged in the casing pipe beneath the tamping plate 8, makingit difficult to extrude the sand from the lower end of the casingpipe 1. However, if the above distance is too little, then thecompacting of the sand will not be performed sufficiently inside thecasing pipe 1 beneath the tamping plate 8. As the result, the sand piledischarged from the lower end of the casing pipe 1 might be compressedby the soil pressure of the surrounding soil or by the excess pore waterpressure, thus producing a sand pile with too small diameter of asand'pile which is interrupted partway along its length.

It has been recognized through experiments that the best result can beobtained if the position of the tamping plate 8 at its lowest movablepoint is at a distance of approximately A D to D above the lower end ofthe casing pipe 1, where D denotes the diameter of the casing pipe 1.

As has been illustrated heretofore, the machine according to the presentinvention has made it possible to obtain not only a sand pile with adiameter equal to that of the casing pipe to be used in the sand drainmethod by driving the casing pipe into the ground to a predetermineddepth and thereafter pulling the casing pipe continuously upwardly, butalso to form a compacted sand pile with a diameter larger than that ofthe casing pipe freely at a predetermined diameter-expansion ratio byadjusting the pulling speed of the casing pipe to a proper rate.

When a compacted sand pile is to be formed with a diameter larger thanthat of the casing pipe by means of the conventional sand pile formingmachines, it becomes necessary, as shown in FIG. 11, to repeat thepulling and redriving actions of the casing pipe. As a result, the sandpile 14 thus formed will have a shape as shown in FIG. 12, whichresembles inverted cones piled up, so that it is impossible to form agood sand pile with a uniform diameter along, its length.

In the case of forming a compacted. sand pile with an expanded diameterby means of the machine according to the present invention, it becomesunnecessary to repeat the pulling and redriving of the casing pipe as inthe case of using the conventional sand pile forming machines, so thatthe execution efficiency in a sand pile forming process can be greatlyincreased.

Moreover, it becomes possible by the machine according to the presentinvention to form a sand pile with a shape suitable for use as a drain,without any diameter reduction nor disruption along its length.

Also, in the sand pile forming process using the machine according tothe present invention it becomes possible to pull out the casing pipecontinuously and furthermore to form a compacted sand pile with anyrequired diameter through the adjustment of the pulling speed.Therefore, the machine for continuously forming sand piles according tothe present invention has the advantage, as compared with thoseconventional sand pile forming machines which require repetition ofpulling and redriving, in that the sand pile forming process can beautomated quite easily by automatic controlling means.

Furthermore, it becomes possible with the machine of the presentinvention to freely and continuously form a compacted sand pile withvarying diameters corresponding to the character of each layer of thesoft ground in case when the soft ground shows different characteristicsby layer.

It is especially difficult with the conventional sand pile formingmachines to discharge sand from the lower end of the casing pipe if andwhen the sand to be used is unfavorable in nature, such as, for example,sand with unsuitable grain size, sand containing clayey soil, or sandwith a high water content. If the machine according to the presentinvention is used, however, the discharge of sand is carried outforcibly by the tamping plate, thus making it possible to perform asatisfactory sand discharging operation even when unfavorable sandmaterials as mentioned above are to be used, whereby sand piles eachhaving a good shape can be formed efficiently.

What is claimed is:

1. A machine for continuously forming sand piles comprising a casinghaving upper and lower ends, a hopper connected to said casing near theupper end thereof for supplying sand thereto, a vibratory pile driver atthe upper end of the casing and above the hopper, ram means in saidcasing for undergoing reciprocatory movement therein, means at the upperend of the casing engaging the ram means to reciprocate the ram means inthe casing, said ram means having a lower end and including a tampingplate at said lower end, said tamping plate having a lowennost end ofstroke position in the casing which is a small distance above the lowerend of the casing and having a cross-sectional area substantiallysmaller than the crosssectional area of the casing, and means at the topof the casing by which the casing, can be lifted from the ground afterbeing sunk therein and sand has been supplied via the hopper to thecasing, said ram means being reciprocably moved in the casing while thelatter is being continuously lifted out of the ground and the vibratorypile driver is operated continuously.

2. A machine as claimed in claim 1, wherein said means to reciprocatethe ram means comprises a cylinder, a piston in said cylinder andattached to the ram means, an outside driving source including apressure fluid source connected to said cylinder, an electromagneticservo-valve between the pressure fluid source and the cylinder, andmeans for controlling said electromagnetic servo-valve.

3. A machine as claimed in claim 1, wherein said tamping plate comprisesa circular disc including an upper portion of conical shape, the crosssection of said tamping plate having an area approximately equal toone-fourth of the area of thecasing.

4. A machine as claimed in claim 1, wherein said tamping plate comprisesa plurality of vertical plates disposed in a radial pattern around theaxes of reciprocation of the ram means. said plates having across-sectional area approximately equal to one-fourth of the area ofthe casing.

5. A machine as claimed in claim I, wherein said tamping plate comprisesan opening and closing plate assembly including a pair of semicirculardiscs pivotably joined together and capable of opening only by pivotingdownwardly to form an inverted V shape.

6. A machine as claimed in claim 1, wherein the distance of said tampingplate above the lower end of said casing at the end of stroke positionis between one-half and the full diameter of said casing.

7. A machine as claimed in claim 1, wherein the reciprocatory motion ofsaid tamping plate is approximately 30 to 60 cpm in frequency and itsstroke is between one-sixth and the full diameter of said casing.

1. A machine for continuously forming sand piles comprising a casinghaving upper and lower ends, a hopper connected to said casing near theupper end thereof for supplying sand thereto, a vibratory pile driver atthe upper end of the casing and above the hopper, ram means in saidcasing for undergoing reciprocatory movement therein, means at the upperend of the casing engaging the ram means to reciprocate the ram means inthe casing, said ram means having a lower end and including a tampingplate at said lower end, said tamping plate having a lowermost end ofstroke position in the casing which is a small distance above the lowerend of the casing and having a cross-sectional area substantiallysmaller than the cross-sectional area of the casing, and means at thetop of the casing by which the casing, can be lifted from the groundafter being sunk therein and sand has been supplied via the hopper tothe casing, said ram means being reciprocably moved in the casing whilethe latter is being continuously lifted out of the ground and thevibratory pile driver is operated continuously.
 2. A machine as claimedin claim 1, wherein said means to reciprocate the ram means comprises acylinder, a piston in said cylinder and attached to the ram means, anoutside driving source including a pressure fluid source connected tosaid cylinder, an electromagnetic servo-valve between the pressure fluidsource and the cylinder, and means for controlling said electromagneticservo-valve.
 3. A machine as claimed in claim 1, wherein said tampingplate comprises a circular disc including an upper portion of conicalshape, the cross section of said tamping plate having an areaapproximately equal to one-fourth of the area of the casing.
 4. Amachine as claimed in claim 1, wherein said tamping plate comprises aplurality of vertical plates disposed in a radial pattern around theaxes of reciprocation of the ram means, said plates having across-sectional area approximately equal to one-fourth of the area ofthe casing.
 5. A machine as claimed in claim 1, wherein said tampingplate comprises an opening and closing plate assembly including a pairof semicircular discs pivotably joined together and capable of openingonly by pivoting downwardly to form an inverted V shape.
 6. A machine asclaimed in claim 1, wherein the distance of said tamping plate above thelower end of said casing at the end of stroke position is betweenone-half and the full diameter of said casing.
 7. A machine as claimedin claim 1, wherein the reciprocatory motion of said tamping plate isapproximately 30 to 60 c.p.m. in frequency and its stroke is betweenone-sixth and the full diameter of said casing.